#1 same virtual address in kernel and user

[Tomasz Motylewski]

At the moment given mbuff may be mapped at the same
virtual address in many processes.

But this address differs from the kernel address - the
one returned by vmalloc.

It would be useful to get access to mbuff's memory at
the same address everywhere, because then pointers may
be stored inside.

Only address offsets are allowed in the current
versions.